首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A very interesting and important development in science is a device called laser. A laser is a machine which produces a light be
A very interesting and important development in science is a device called laser. A laser is a machine which produces a light be
admin
2015-01-31
91
问题
A very interesting and important development in science is a device called laser. A laser is a machine which produces a light beam. The light produced by a laser is a very special kind of light. The light, called laser beam, is powerful and can be made to do many things. The laser was first developed in 1960, about half a century ago.
There are many different uses for lasers and several different types have been developed. Some use gases to produce the light beam. The gases are heated and cooled, and these processes cause the gases to produce energy in the form of light. One special point of lasers is that the light beam can be stored. If the stored light is then suddenly let go, it is extremely powerful. The light from a laser beam can be used either by storing it and letting it go suddenly, or by using it in a continuous stream.
There are three important areas where the control of the laser beam has been put into use by scientists. These areas are industry, communications, and medicine. In each area, the scientists have been able to use the laser to do things that they could not do in another way. The laser has been very helpful.
In industry, the laser beam has been used for measurement and drilling. When something large is being built—for example, a large bridge—it is important to have very accurate measurements. By accurate measurement, lasers are also helpful in laying down pipelines over long distances. As lasers become more common in industry, there will be more and more uses for them.
A laser beam is______.
选项
A、a light produced half a century ago
B、powerful and has many uses
C、a very important device
D、a kind of light from space
答案
B
解析
细节题。细节题。根据短文第一段第四句The light,called a laser beam,ispowerful and can be made to do many things.可知选项B正确。
转载请注明原文地址:https://kaotiyun.com/show/Y5q7777K
0
大学英语四级
相关试题推荐
A、Sheoughttobuyherowncopymachine.B、Sheneedstobuyapackageofpaper.C、Shehasalreadyusedenoughpaper.D、Sheshoul
ThecountriesthathavelefttheUnitedStatesbehindinmathandscienceeducationhaveonethingincommon:Theyofferthesam
ThecountriesthathavelefttheUnitedStatesbehindinmathandscienceeducationhaveonethingincommon:Theyofferthesam
ThecountriesthathavelefttheUnitedStatesbehindinmathandscienceeducationhaveonethingincommon:Theyofferthesam
ThecountriesthathavelefttheUnitedStatesbehindinmathandscienceeducationhaveonethingincommon:Theyofferthesam
ThecountriesthathavelefttheUnitedStatesbehindinmathandscienceeducationhaveonethingincommon:Theyofferthesam
随机试题
Severaltypesoffinancialriskareencounteredininternationalmarketing;themajorproblemsincludecommercial,politicalris
_______是指开业一周年、三周年、十周年、五十周年等纪念。周年庆典有利于加深企业在公众心目中的形象,是企业前进的加油站。
某内科医生出门诊,发现心脑血管系统、呼吸系统、肿瘤等疾病占大多数,为整理各系统疾病,确定指标的性质是
患者,女性,26岁,左下腹隐痛伴脓血便2年,加重2个月,诊断为溃疡性结肠炎。下列护理措施中哪项不正确()
1999年4月1日,甲公司持有对乙公司的长期股权投资500000元(500000股,每股面值1元),采用成本法核算。1999年5月1日,乙公司宜告分派1998年度的现金股利,每股0.02元。假定甲公司没有再追加对乙公司的投资。据此计算,1999年6月30日
()指的是债券的平均到期时间,从现值角度度量了债券投资者回收其全部本金和利息的平均时间。
服务营销战略中,企业内部营销的对象有()。
简述经济体制与经济制度的关系。
某市的红光大厦工程建设任务进行招标。有四个建筑公司投标。为简便起见,称它们为公司甲、乙、丙、丁。在标底公布以前,各公司经理分别作出猜测。甲公司经理说:“我们公司最有可能会中标,其他公司不可能。”乙公司经理说:“中标的公司一定出自乙和丙两个公司之中。”丙公司
由于预测明年经济增长速度会放慢,因而引起了最近美元币值的下跌。但是如果没有政府的巨额预算赤字,该预测就不会对美元有负面影响,因此必须降低该赤字来防止将来的货币贬值。以下哪项如果正确,将最严重地削弱关于如何防止将来货币贬值的结论?
最新回复
(
0
)